Support arm for a clamping and centering element of a gripper frame for holding three-dimensional components in the motor vehicle industry

ABSTRACT

A support arm for a clamping and/or centering element of a gripper frame for holding three-dimensional components includes an adjustment mechanism, such as a ball that can pivot and/or a cylindrical pin that slide and rotate, held in a clamping and release unit with clamping jaws that can be radially clamped. A mechanical, hydraulic, pneumatic, or electromagnetic force generator applied to at least one of the clamping jaws is integrated in the support arm and generates a clamping force, against whose force the clamping jaws can be released by means of an adjusting element of a driven eccentric or cam mechanism.

The invention relates to a support arm for a clamping and/or centring element of a gripper frame for holding three-dimensional components, in particular in the motor vehicle industry, in which an adjustment mechanism is integrated, with at least one ball that can pivot and/or a cylindrical pin that can slide and rotate, in either case held in a clamping and release unit, wherein the clamping and release unit encompasses the ball and/or the cylindrical pin with clamping jaws that can be axially or radially clamped.

Gripper frames of known art for holding three-dimensional components in the manufacture of motor vehicle bodywork (U.S. Pat. No. 6,722,842 B1) have clamps and centring pins that enable a three-dimensional component to be held in the correct position. Such gripper frames can be moved with handling robots in space, wherein a three-dimensional component held by a gripper frame can be transported to the location, and held here in the correct position, where it is to be attached to a motor vehicle body and/or connected with other bodywork components. Since for the bodywork of a vehicle several three-dimensional components are to be manipulated, it is of known art to adapt the gripper frame with regard to its clamping and centring elements held by support arms to the geometry of the component to be manipulated in each case. For this purpose an adjustment mechanism is integrated in each support arm, which in a clamping and release unit includes at least one ball and one cylindrical pin, which enable pivoting, sliding and rotation of the clamping and centring elements held by the support arm. The clamping and release unit for both the ball and also the cylindrical pin consists essentially of clamping shells or clamping jaws that can be clamped up using clamping bolts. Accordingly this requires time-consuming manual work to adjust the gripper frame to the geometry of a new component with respect to its clamping and centring elements.

The object of the present invention is to create a support arm for a clamping and/or centring element of a gripper frame for holding three-dimensional components of the kind cited in the introduction, which enables the adjustment of a gripper frame in a simple manner to different geometries of three-dimensional components.

This object is achieved according to the invention in that for the generation of the clamping force of the clamping jaws a mechanical, hydraulic, pneumatic, or electromagnetic force generator applied to at least one of the clamping jaws, in particular a compression spring, is integrated in the support arm, against whose force the clamping jaws can be released by means of an adjusting element of a driven eccentric or cam mechanism.

In a gripper frame fitted with the support arm according to the invention in the event of an exchange from one three-dimensional component to a three-dimensional component with another geometry the adjustment of clamping and/or centring elements held by support arms can easily be undertaken without time-consuming assembly tasks, such as the release of screw bolts on clamping shells, clamping jaws and similar, in that the clamping jaws of the ball or the cylindrical pin are released by means of the adjusting element of the eccentric and cam mechanism against the clamping force of the force generator exerted on the clamping jaws. The clamping and centring elements can then be moved into the required position, where they are fixed purely by the removal of the release mechanism. In the case of a ball, the released clamping jaws enable not only a rotation, but also a pivoting about their centre, while in the case of a cylindrical pin the clamping jaws enable the rotation of the cylindrical pin about its axis, but also its movement in an axial direction. By clamping jaws are to be understood not only segments, but also rings and slitted sleeves. Which particular embodiment the clamping jaws can have depends essentially on the “ball” or “pin” component to be clamped.

According to one embodiment of the invention, the clamping jaws are configured as shells engaging with mutually opposing halves of the ball or cylindrical pin, whose separation distance can be adjusted by means of adjustment. In the case of a ball the clamping jaws are preferably configured in a ring- or calotte-shaped manner.

In what follows the invention is elucidated in more detail by means of a drawing representing various examples of embodiment. In the individual figures:

FIG. 1 shows in a schematic representation a side view of a support arm for a clamping element with two ball joints and a longitudinal extension,

FIG. 2 shows an axial section of a mechanical clamping and release unit of a ball joint,

FIG. 3 shows an axial section of a mechanical clamping and release unit of an embodiment other than that in FIG. 2, and

FIG. 4 shows an axial section of a clamping and release unit for a sliding joint with a hollow cylindrical pin in an embodiment similar to that of FIG. 2.

The support arm 1 represented in FIG. 1 for a clamping element 2 includes two ball joint connections 3, 4 and a longitudinal extension 5 arranged between them. The clamping element 2 is carried by a pin 3 b formed onto the ball 3 a of the ball joint 3. A pin 4 b formed onto the ball 4 a of the ball joint 4 carries an attachment flange 6, with which the support arm 1 can be attached to a bracket, not represented, of a gripper frame. Clamping and release units, that have yet to be described in detail, are assigned to the ball joints 3, 4 and to the longitudinal extension 5; these units make it possible, when a clamping and release unit is released, for the clamping element 2 to be moved relative to the attachment flange 6 from one position in space to another position in space and here fixed. In this process the ball joints 3, 4 enable both rotational and pivoting movements.

In the ball joint 3 in FIG. 2 ring-shaped clamping jaws 7 a, 7 b engage with both halves of the ball 3 a. The clamping jaw 7 a is part of a housing 7, in which the clamping jaw 7 b is guided. The clamping jaw 7 b is pushed in the direction of the clamping jaw 7 a by means of a compression spring designed as a plate spring 8; this spring is supported on an abutment plate 9 of the housing 7. A tension bolt 10 engages with the clamping jaw 7 b; by means of an eccentric mechanism 11 this bolt can pull the clamping jaw 7 b away from the ball 3 a against the compression force of the compression spring 8. The eccentric mechanism 11 is connected via a lever arm 13 with a pneumatic drive 12 in the form of a piston-cylinder unit. In the position represented in FIG. 2 the ball 3 a is locked in position by means of the clamping jaws 7 a, 7 b.

The example of embodiment in FIG. 3 differs from that of FIG. 2 only in the drive of the tension bolt 10. The tension bolt 10 is supported on a torque-proof headplate 14 mounted in ball bearings; a cam mechanism is arranged between the headplate 14 and the support plate 9; it consists of a radial curve 15 formed on the rear face of the abutment plate 9 and a drive block 16, which supports itself on the radial curve 15 with the aid of opposing trunnions 16 a mounted in roller bearings. The drive block 16 is driven by an electric motor 17 and a gearbox 18. The output from the gearbox 18 is coupled via drive arms 19 with the drive block 16 for the transfer of torque. Thus the drive block 16 can be rotated by means of the electric motor 17, whereby it exerts an axial adjusting movement onto the headplate 14, as a result of which the clamping jaw 7 b is released.

The example of embodiment in FIG. 4 differs from that in FIG. 2 only in that it is not a ball, but a cylindrical body, and in particular a circular cylindrical tube 20, that is locked in position with the clamping and release unit. Accordingly the clamping jaws 21 a, 21 b are also not designed to be ring-shaped, but shell-shaped, wherein under “shell-shaped” is to be understood not only full shells, but also axial bars acting together in pairs. It is to be understood that the tension bolt 10 can be moved not only by means of an eccentric mechanism with a pneumatic drive 12 according to FIG. 2, but also by means of the drive in FIG. 3 with a cam mechanism and an electric motor. 

1. A support arm for a clamping and/or centering element of a gripper frame for holding three-dimensional components, in which an adjustment mechanism is integrated, with at least one ball that can pivot and/or a cylindrical pin that can slide and rotate, in either case held in a clamping and release unit, wherein the clamping and release unit encompasses the at least one ball and/or the cylindrical pin with clamping jaws that can be axially or radially clamped, wherein a mechanical, hydraulic, pneumatic, or electromagnetic force generator applied to at least one of the clamping jaws and integrated in the support arm generates a clamping force of the clamping jaws, against whose force the clamping jaws can be released by means of an adjusting element of a driven eccentric or cam mechanism.
 2. The support arm according to claim 1, wherein the force generator is a compression spring.
 3. The support arm according to claim 1, wherein the clamping jaws are configured as shells engaging with mutually opposing halves of the at least one ball or cylindrical pin, whose separation distance can be adjusted by means of the eccentric or cam mechanism.
 4. The support arm according to claim 3, wherein the clamping jaws are configured in a ring- or calotte-shaped manner and encompass the at least one ball. 